Quick release stopper rod for steel mill ladle

ABSTRACT

In the combination of a steel mill ladle having a bottom port for release of molten metal from the ladle, a stopper rod in the ladle to open and close the bottom port, and a gooseneck on the ladle to support and control the stopper rod, the present invention comprises: equipping the stopper rod with a bail for use by a crane to lift the stopper rod out of the ladle with provision for lost motion between the bail and the stopper rod; and the provision of attachment means to releasably connect the stopper rod to the gooseneck on the ladle with the attachment means releasable by the lost motion between the bail and the stopper rod. Thus, when a crane initially exerts lifting force on the bail to lift the stopper rod out of the ladle, the stopper rod is automatically released from the gooseneck on the ladle.

[4 Nov. 19, 1974 United States Patent Springer Primary Examiner-R0bert B. Reeves QUICK RELEASE STOPPER ROD FOR STEEL MILL LADLE Assistant Examiner-David A. Scherbel Attorney, Agent, or Firm-Jess M. Roberts [76] Inventor: Joseph E. Springer, 11211 Monte Vista, Ontario, Calif. 91761 Feb. 20, 1973 [22] Filed:

[21] Appl. No.: 334,006

trol the stopper rod, the present invention comprises: equipping the stopper rod with a bail for use a 315 crane to lift the stopper rod out of the ladle with provision for lost motion between the bail and the sto Pp References cued rod; and the provision of attachment means to releas- UNITED STATES PATENTS ably connect the stopper rod to the gooseneck on the 222/5 59 UX ladle with the attachment means releasable by the lost motion between the bail and the stopper rod. Thus,

FOREIGN PATENTS OR APPLICATIONS when a crane initially exerts lifting force on the bail to 1,028,231

2,810,169 10/1954 Hofer...........

lift the stopper rod out of the ladle, the stopper rod is automatically released from the gooseneck on the ladle.

2/1953 France.......... 162,864 4/1949 Germany............................

21 Claims, 10 Drawing Figures 1| llllal .n i: I

PATENTEL NOV] 9 I974 SHEEI 10F 3 m ll-lllllll. F

' PATENTELHUVISISM I sum EM 3 3'848 T QUICK RELEASE STOPPER ROD FOR STEEL MILL LADLE BACKGROUND OF THE INVENTION Molten steel is commonly poured from a bottom port of a huge ladle that is suspended from an overhead crane. For manual control of the pouring operation, a stopper rod inside the ladle is carried by a support structure on the ladle that is commonly termed a gooseneck. The gooseneck not only supports the stopper rod but is also operable to raise and lower the stopper rod to open and close the bottom port of the ladle. To protect the steel stopper rod from the molten metal in the ladle, it is equipped with a replaceable refractory casing and the bottom outlet of the ladle is equipped with a replaceable refractory bushing of graphite to receive the nose of the stopper rod. By the time a pouring operation is completed and the slag has been discarded through the bottom port of the ladle, the refractory casing of the stopper rod and the graphite bushing are so badly eroded that they must be replaced.

In the conventional construction of the gooseneck on a ladle, a pair of short rigid horizontal arms of the gooseneck straddle the stopper rod and a pair of nuts on the stopper rod are manually tightened against the upper and lower surfaces respectively of the pair of arms to clamp the stopper rod to the gooseneck. To prepare for substitution of a newly encased stopper rod for a used stopper rod, a crane is maneuvered into engagement with the upper end of the used stopper rod and the two nuts on the stopper rod are manually retracted to release the used stopper rod from the gooseneck. Then the used stopper rod is manually shifted laterally clear of the pair of rigid arms of the gooseneck to permit the stopper rod to be lifted out of the ladle by the crane.

After a new graphite bushing is substituted for the eroded bushing in the bottom of the ladle, a newly encased stopper rod is lowered by a crane into the ladle. It is necessary, however, to lower the new stopper rod along a path that is displaced from alignment with the bottom port of the ladle because of the presence of the two rigid arms of the gooseneck. Consequently, the descending new stopper rod must be manually tilted and maneuvered into position for seating in the graphite bushing to close the bottom port of the ladle. Finally, the tilted stopper rod must be swung into upright position between the two rigid arms of the gooseneck to permit the nuts on the stopper rod to be tightened manually into clamping engagement with the two rigid arms.

In a typical procedure, a workman enters the ladle before it is completely cool to maneuver the new stopper rod. He finds it necessary first to tilt the stopper rod clear of the two rigid arms of the gooseneck and to kick the lower end of the tilted stopper rod into engagement with the bottom port of the ladle.

Obviously, considerable labor cost is involved in the various operations of: manually loosening the two nuts on the used stopper rod to release the used stopper rod from the gooseneck; maneuvering the used stopper rod as the crane lifts the used stopper rod out of the ladle; and manually tilting and kicking a newly encased stopper rod to maneuver it into position between the pair of rigid arms of the gooseneck when the crane lowers the newly encased stopper rod into the ladle.

SUMMARY OF THE INVENTION The primary object of the invention is to greatly reduce the labor and time required both to withdraw a used stopper rod from a ladle and to substitute a newly encased stopper rod.

A more specific object of the invention is to provide the gooseneck with attachment means to connect a stopper rod to the gooseneck, which attachment means is releasable automatically in response to initial lifting force exerted on a used stopper rod when a crane is employed to lift the used stopper rod out of the ladle.

Another object of the invention is to cause the attachment means to thrust the used stopper rod laterally away from the gooseneck to keep the used stopper rod from catching on the gooseneck as the crane lifts the used stopper rod out of the ladle.

A further object of the invention is to simplify the replacement of a stopper rod to such extent as to make it possible to replace a stopper rod safely in a hot ladle and thus eliminate the necessity for the usual long time period to permit a hot ladle to cool down after a pouring operation.

A typical ladle is equipped with a so-called gooseneck or support structure for raising and lowering the stopper rod to open and close the bottom port of the ladle, but in the present invention the gooseneck does not have the usual pair of rigid arms that straddle the stopper rod and are engaged from above and below by nuts on the stopper rod. Instead, the gooseneck is equipped with releasable attachment means comprising an end portion of the gooseneck for engagement from above by an upper nut on the stopper rod and a cooperating rotary engagement member for pressure from below by a washer backed by a lower nut on the stopper rod. The engagement member is rotatable between an effective position for cooperation with the lower nut and a release position to free the stopper rod from the gooseneck.

A latch releasably holds the engagement member at its effective position so that with the upper nut engaging the end portion of the gooseneck and with the washer tightened by the lower nut against the latched rotary engagement member, the stopper rod is effectively anchored to the gooseneck.

The upper and lower nuts are part of an assembly that is screw threadedly mounted on the stopper rod to cooperate with the attachment means on the gooseneck for releasable anchorage of the stopper rod. This assembly includes bail means on the upper end of the stopper rod for engagement by a crane to withdraw a used stopper rod from the ladle, Le, a stopper rod the refractory casing of which has been eroded in a metal pouring operation. Subsequently, the crane may be engaged with a bail means on a newly encased replacement stopper rod to lower the replacement stopper rod into the ladle. The bail means has a lost motion connection with the stopper rod so that the bail means is movable relative to the stopper rod between a lower relaxed position and an upper load-bearing position at which it is capable of carrying the weight of the stopper rod. For this purpose the assembly on the stopper rod includes an upwardly extending tubular member over which the bail means slidably telescopes.

The required lost motion is provided by cooperating shoulders on the tubular member of the assembly and the surrounding bail means respectively. The latch for immobilizing the rotary engagement member on the gooseneck is operatively connected to the bail means so that upward movement of the bail means from its lower relaxed position to its upper load-bearing position lifts the latch to release the rotary engagement means on the gooseneck from its effective position. Thus, when a crane in engagement with the bail means initially pulls upward to lift the stopper rod, the stopper rod is automatically released from the gooseneck on the ladle.

In the upward movement of a used stopper rod out of the ladle the rising stopper rod should be momentarily pushed away from the end of the gooseneck to be sure that the rising stopper rod does not engage the gooseneck and thus cause the crane to exert damaging lifting force on the gooseneck. In this regard a feature of the invention is the concept of shaping and dimensioning the rotary engagement member to exert lateral thrust on the released stopper rod to cause the desired momentary shift of the stopper rod laterally away from the gooseneck.

When the released used stopper rod is raised out of the ladle, it swings the engagement member on the gooseneck out of the way to its upper released position and thus clears the path for installing a newly encased stopper rod.

A further feature of the invention is the concept of constructing and arranging the assembly on the stopper rod to serve as a carriage to cooperate with a track to move the stopper rod through an oven for the purpose of drying and hardening a ceramiccasing on the stopper rod. This feature greatly reduces the time required to recondition a stopper rod.

The various features, objects and advantages of the invention may be understood from the following detailed description and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings which are to be regarded as merely illustrative:

FIG. 1 is a side elevational view, partly in section, showing a stopper rod releasably engaged by a gooseneck on a ladle;

FIG. 2 is an enlargement of a portion of FIG. 1, partly in section and partly in side elevation;

FIG. 2A is an elevational view of the latch member in FIGS. 1 and 2; a

FIG. 3 is a fragmentary side elevational view as seen along the line 33 of FIG. 2;

FIG. 4 is a fragmentary transverse section taken along the line 4-4 of FIG. 2;

FIG. 5 is a fragmentary elevational view partly in section, showing how lost motion between the bail means and the stopper rod unlatches the engagement member on the gooseneck in response to initial lifting force on the bail means by a crane;

FIG. 6 is a fragmentary elevational view similar to FIG. 5 showing how the elevation of the released stopper rod by the crane swings the rotary engagement member on the gooseneck upward out of the way;

FIG. 7 is a perspective view of a second embodiment of the invention;

FIG. 8 is a side elevational view, partly in section,

showing the second embodiment of the invention anchoring a stopper rod to the gooseneck of a ladle; and

DETAILED DESCRIPTION OF THE EMBODIMENTS OF THE INVENTION FIG. 1 shows a ladle, generally designated 10, which in a well known manner is provided with trunnions (not shown) to permit the ladle to be maneuvered by an overhead crane (not shown). The ladle has the usual bottom pouring port 12 that is provided with the usual replaceable graphite bushing 14 and the bottom port is normally closed in the usual manner by the nose of an upwardly extending stopper rod 15.

A support structure in the form of a so-called gooseneck, generally designated 16, is suitably mounted on the ladle and is manually operable from outside of the ladle to raise and lower the stopper rod 15 to control the pouring of molten steel through the bottom port 12.

The upper portion of the stopper rod 15 has an extensive screw thread 18 and the remaining portion of the stopper rod is enclosed by a casing comprising a series of ceramic sleeves 20, which casing is eroded by molten steel and must be replaced after a metal pouring operation.

The gooseneck 16 is provided with suitable attachment means which releasably engages a cooperating assembly on the stopper'rod to releasably connect the stopper rod to the gooseneck. In the construction shown the engagement means on the gooseneck 16 comprises an upwardly projecting end portion 22 of the gooseneck and an engagement member, generally designated 24, that is rotatably mounted on the gooseneck. The engagement member 24 has two arms 25 that straddle the gooseneck and are fixedly mounted on opposite ends of a short shaft 26, best shown in FIG. 4, that is journalled in a transverse bore of the gooseneck. The engagement member 24 is rotatable between a lower effective position shown in FIG. 2 and an upper limit release position shown in FIG. 6 and a transverse stop bar 28 that bridges the two arms 25 abuts the under side of the gooseneck at the lower effective position of the rotary engagement member shown in FIG. 2 and abuts the forward edge of the gooseneck at the upper release position of the engagement member shown in FIG. 6. The rotary engagement member 24 may be releasably locked in its lower effective position by seating a latch member 30 in three aligned transverse grooves as shown in FIGS. 2 and 4. The three grooves are a central transverse groove 32 in the gooseneck 16 and two grooves 34 in the two arms 25 respectively of the en-' gagement member 24.

The assembly on the stopper rod 15 that cooperates both with the end portion 22 of the gooseneck l6 and the engagement member 24 on the gooseneck includes the following components: a washer 35 that loosely embraces the stopper rod 15 and serves as a lower lateral projection on the stopper rod; a lower nut 36 that is separate from the washer and is threaded onto the stopper rod to support the washer from below; an upper lateral projection in the form of an upper nut 38 that is threaded onto the stopper rod and is integral with an upwardly extending tube 40 that surrounds the stopper rod; and an upper cylindrical body 41 of a bail means, generally designated 42, that slidingly telescopes over the upwardly extending tube 40.

The washer 35 of the assembly is provided with a pair of diametrically opposite radial ribs 44 in the form of short rods welded to the washer and the two arms 25 of the rotary engagement member 24 which are spaced apart to straddle the stopper rod are formed with notches 45 which engage the two radial ribs 34 respectively from above when the engagement member is at its lower effective position shown in FIG. 2. Welded to the underside of the upper nut 38 is a ring 46 having a downwardly extending circumferential flange 48 for engagement with the previously mentioned upwardly projecting end portion 22 of the gooseneck. As shown in FIG. 2 the peripheral flange 48 of the ring 46 is inwardly tapered and the upwardly projecting end portion 22 of the gooseneck has a tapered rear shoulder 50 (FIGS. 2 and 6) which, as shown in FIG. 4, is arcuate in plan to mate with the inwardly tapered peripheral flange of the ring.

The tube 40 that extends upwardly from the upper nut 38 has an upper end wall 52 and the tube is embraced by a fixed collar 54 that provides the tube with a downwardly facing outer circumferential shoulder 55. In the construction shown in FIG. 2 the cylindrical body 21 of the bail means 42 has an upper end wall 56 that overhangs the upper end wall 52 of the tube 40 and a centrally located steel ball 58 is welded to the underside of the wall 56 to serve as a spacer between the two end walls.

The bail means 42 has a bail 60 for engagement by a crane to lift the stopper rod andin the absence of the crane the bail means is at its lower relaxed position shown in FIG. 2 where the steel ball 58 supports the bail means on the upper end wall 52 of the tube 40. The lower end of the bail means 42 is formed with a thick inner circumferential flange 62 which provides the bail means with an upwardly facing inner circumferential shoulder 64 and a downwardly facing inner circumferential shoulder 65. Thus, the bail means 42 has a lost motion connection with the stopper rod 15 with the magnitude of the lost motion determined by the normal axial distance between the downwardly facing outer circumferential shoulder 55 of the tube 40 and the upwardly facing inner circumferential shoulder 64 of the bail means. When a crane applies lifting force to the bail 60 the bail means 42 is raised from its lower relaxed position shown in FIG. 2 to its upper load-bearing position shown in FIG. 5 where the inner circumferential shoulder 64 of the bail means abuts the outer circumferential shoulder 55 of the tube 40 to transmit the weight of the stopper rod 15 to the crane. The steel ball 58 may be omitted to permit the bail means 42 to rest on the upper nut 38 at the relaxed position of the connector, the nut providing an upwardly facing outer circumferential shoulder 66 for abutment by the downwardly facing inner circumferential shoulder 65 of the bail means.

Welded to the outer circumference of the bail means 42 is a suitable bracket 68 to which the latch member 30 is connected, a clevis 70 engaging the latch member as shown in FIGS. 2 and 2A with a pin 72 of the clevis extending through a bore 74 in the bracket. At the lower relaxed position of the bail means 42 shown in FIG. 2, the latch 30 releasably locks the rotary engagement member 24 in its lower effective position, but when the bail means is raised by a crane to its upper load-bearing position in FIG. 5, the lost motion of the bail means lifts the latch 30 to its free position to release the rotary engagement member for upward rotation to release the stopper rod from the gooseneck 16.

The manner in which this first embodiment of the invention serves its purpose may be readily understood from the foregoing description.

The described assembly that cooperates with the attachment means may be releasably mounted on the stopper rod 15 by first screwing the lower nut 36 onto the stopper rod, then dropping the washer 35 onto the nut and, finally, by screwing the upper nut 38 onto the stopper rod. A plurality of stopper rods 15 are employed interchangeable in a steel mill and the described assembly may be transferred from stopper rod to stopper rod or each of the stopper rods may be equipped with an assembly that remains with the stopper rod.

In preparation for installing a newly encased stopper rod in a ladle, the engagement member 24 is rotated to its lower effective position and the two nuts 36 and 38 are adjusted at ample spacing on the stopper rod. A crane engaged with the bail 60 lowers the stopper rod into the ladle to seat the nose of the stopper rod in the graphite bushing 14 to close the bottom port 12 of the ladle, the crane being lowered sufficiently to permit the bail means 42 to drop to its lower relaxed position thereby to permit the latch 30 to be seated in the aligned grooves 32, 34 to lock the engagement member in its lower effective position.

The upper nut 38 is then spun downward into engagement with the upwardly projecting end portion 22 of the gooseneck and then the washer 35 is raised to bring its two radial ribs 44 into engagement with the corresponding notches 35 of therotary engagement member 24. Finally, the lower nut 36 is tightened upward against the washer 35 to cooperate with the upper nut 38 to clamp the stopper rod to the gooseneck 16.

To remove a stopper rod 15 from the ladle, a crane is again engaged with the bail 60 of the bail means 42 to apply lifting force to the stopper rod 15. Initial up: ward movement of the bail means 42 lifts the latch 30 free from the gooseneck to release the engagement member 24 for release of the stopper rod. When the lifting action of the crane brings the inner circumferential shoulder 64 of the bail means 42 into abutment with the outer circumferential shoulder 55 of the tube 40, the weight of the stopper rod is transferred to the crane and the stopper rod is lifted out of its seat in the graphite bushing 14.

With the two radial ribs 45 of the washer 35 in engagement with the corresponding notches 44 of the engagement member 24, the upward rotation of the engagement member 24 causes the upward arcuate travel of the notches 45 to thrust the rising stopper rod laterally to position the washer 35 and the nut 36 clear of the end of the gooseneck as indicated by the dotted positions of the washer and nut in FIG. 5. Continuation of the rising movement of the stopper rod 15 causes the washer to swing the rotary engagement member 24 to its upper limit position shown in FIG. 6.

Since the installing of a stopper rod in a ladle requires only manipulation of the two nuts 36 and 38 and perhaps additional manipulation of the latch 30, it is apparent that a workman can install the stopper rod in a relatively hot ladle at minimum hazard to himself because it is not necessary for the workman to enter the ladle. It is also apparent that the stopper rod may be withdrawn from a very hot ladle immediately after a pouring operation without hazard because it is released from the gooseneck automatically without involving a workman.

The second embodiment of the invention shown in FIGS. 7 and 8 is largely similar to the first embodiment as indicated by the use of corresponding numerals to designate corresponding parts.

The tube 40a that extends upward from the upper nut 38a is relatively short and terminates in an outer circumferential flange or collar 54a which provides a downwardly facing outer circumferential shoulder 55a. The bail means 42a has a heavy inner circumferential flange 62a at its lower end which provides an upwardly facing inner circumferential shoulder 64a to cooperate with the outer circumferential shoulder 55a at the upper load-bearing position of the bail means. The lower end of the bail means has a downwardly facing outer circumferential shoulder 65a which rests on an upwardly facing outer circumferential shoulder 66a of the nut 38a when the connector is at its lower relaxed position. The bail means 42a is formed with a hook instead of a bail for engagement by a crane and the connector is further formed with a handle 76 on one side which forms a loop with which the usual latch 30a is linked. For a purpose which will be explained later, the bail means 42a may have a pair of diametrically opposite external recesses 78.

It is apparent that the second embodiment of the invention functions in the same manner as the first embodiment.

FIG. 9 shows how a pair of opposite rollers 80 may be mounted by corresponding axles 82 on opposite sides of the described bail means 42a to adapt the bail means for travel along a track that is generally designated 84 in FIG. 9. The track 84 comprises two spaced confronting rails 85 that have lower flanges 86 for engagement by the rollers 80 and have upper flanges 88 that are cleared by the previously mentioned side recesses 78 of the bail means 42a. The track 84 extends through an oven that hardens the ceramic casing of a connector rod to prepare the connector rod for reuse. The successive connector rods travel through the oven with enough time in the oven to harden the ceramic casings.

My description in specific detail of the selected embodiments of the invention will suggest various changes, substitutions and other departures from my disclosure within the spirit and scope of the appended claims.

I claim:

1. In the combination of a ladle having a bottom port to pour molten metal, a stopper rod in the ladle to open and close the bottom port and support structure carried by the ladle to support and control the stopper rod, the improvement comprising:

the stopper rod being equipped for cooperation with a crane to lift the stopper rod out of the ladle;

said support structure being equipped with attachment means to releasably connect the stopper rod to the support structure;

said attachment means being variable between a first state to connect the stopper rod to the support structure and a second state to release the stopper rod from the support structure; and

a latch to releasably retain said attachment means in its first state,

said latch being responsive to lifting force on the stopper rod by a crane to release the attachment means for shift from its first state to its second state to release the stopper rod from the support structure.

2. In a combination of a ladle having a bottom port to pour molten metal, a stopper rod to close and open the bottom port and support structure mounted on the ladle to control the stopper rod, the improvement comprising:

attachment means having a first state to connect the stopper rod to said support structure and a second state to release the stopper rod from the support structure;

bail means on the stopper rod engageable by a crane to lift the stopper rod out of the ladle; and

means to shift the attachment means from its first state to its second state in response to lifting force exerted on the bail means, thereby to release the stopper rod from the support structure.

3. In a ladle having a bottom port to pour molten metal, wherein a stopper rod normally closes the bottom port and the stopper rod is releasably connected at its upper end to support structure on the ladle, the combination of:

an engagement member on said support structure movable between a first effective position to engage the stopper rod to connect the stopper rod to the support structure and a second release position to release the stopper rod from the support structure;

means to latch the engagement member at its effective position; and

bail means on the stopper rod for engagement by a crane to lift the stopper rod out of the ladle for replacement of the stopper rod after a pouring operation,

said bail means being movable relative to the stopper rod with lost-motion between a lower relaxed position and an upper load-bearing position to support the stopper rod from the crane,

said latch means being operatively connected to the bail means for release in response to upward movement of the bail means to its upper weight-bearing position,

whereby engaging the crane with the bail means and lifting the bail means to raise the stopper rod out of the ladle causes the latch means to release the engagement member for release of the stopper rod from the support structure.

4. A combination as set forth in claim 3 in which said engagement member at its first efl'ective position extends into the path of vertical movement of the stopper rod and at its second release position is retracted for reduced interference with lowering of a replacement rod into the ladle.

5. A combination as set forth in claim 3 in which said engagement member is rotatable between a lower effective position and an upper release position.

6. A combination as set forth in claim 5,

in which a portion of the engagement member moves in an are between its two positions;

and in which said portion of the engagement member is shaped and dimensioned to shift the stopper rod laterally away from the support structure in the arcuate movement of the engagement member from its effective position to its release position to keep components on the stopper rod from catching on said support structure in the ladle in the course of the upward movement of the stopper rod.

7. A combination as set forth in claim 3 in which the stopper rod has a first lateral projection shaped and dimensioned to engage a fixed portion of said support structure from above the fixed portion and the stopper rod has a second lateral projection for engagement with the engagement member from below the engagement member,

whereby the first lateral projection may cooperate with the fixed portion of the support structure to resist downward axial movement of the stopper rod relative to the support structure and the second lateral projection may cooperate with the engagement member at its effective position to resist upward axial movement of the stopper rod relative to the support structure.

8. A combination as set forth in claim 7 in which at least one of said first and second lateral projections is adjustable towards the other to tighten the engagement of the support structure with the stopper rod.

9. The combination of:

a ladle having a bottom port for pouring moltenmetal;

a stopper rod to control the bottom port;

support structure for the stopper rod carried by the ladle;

attachment means on the support structure; and

an assembly on the stopper rod for engagement by the attachment means,

said attachment means being variable between an effective state to engage the assembly and a release state to release the assembly for withdrawal from the ladle of the stopper rod with the assembly thereon;

said assembly including:

means for engagement by said attachment means in its effective state to connect the stopper rod to said support structure;

a latch to releasably hold the attachment means in its effective state;

bail means for engagement by a crane to lift the stopper rod and the assembly thereon out of the ladle; and

means to release the latch in response to the application of lifting force to the bail means to cause the attachment means to release the stopper rod and the assembly thereon for withdrawal from the ladle by the crane.

10. A combination as set forth in claim 9 in which said attachment means includes both a portion of the support structure and an engagement member rotatably mounted on the support structure;

in which said assembly has an upper lateral projection to engage said portion of the support structure from above;

and in which the assembly has a lower lateral projection to engage said engagement member from below.

11. A combination as set forth in claim 10 in which at least one of said two projections is adjustable relative to the other to permit tightening of the engagement of the attachment means with the assembly.

12. A combination as set forth in claim 10 in which one of said projections is slidable along the stopper rod and is backed by nut means on the stopper rod for adjustment of the one projection relative to the other projection.

13. A combination as set forth in claim 10 in which said latch is operable to releasably interlock the engagement member with the support structure.

14. A combination as set forth in claim 9 in which said assembly is releasably mounted on the stopper rod.

15. A combination as set forth in claim 9 in which said assembly is internally screw threaded for engagement with an external screw thread of the stopper rod to mount the assembly on the stopper rod.

16. A combination as set forth in claim 9 in which said bail means is connected to the stopper rod with lost motion between the bail means and the stopper rod;

and in which said latch is releasable in response to said lost motion.

17. A combination as set forth in claim 16,

in which said assembly has an upwardly extending portion anchored to the stopper rod; in which said bail means is slidably telescoped over said portion to provide said lost motion; I

in which said portion has an outer downwardly facing shoulder and the surrounding bail means has an upwardly facing inner shoulder to contact said downwardly facing shoulder at the upper load-bearing position of the bail means;

and in which cooperating means on said portion and the bail means respectively cooperate to limit the downward movement of the connector relative to said portion at the lower relaxed position of the bail means.

18. A combination as set forth in claim 17 in which said cooperating means comprises an upwardly facing outer shoulder on said portion of the assembly and a downwardly facing inner shoulder on the surrounding bail means.

19. A combination as set forth in claim 17 in which a portion of the bail means overhangs the upper end of said portion of the assembly and rests on said upper end at the lower relaxed position of the bail means.

20. A combination as set forth in claim 19 which includes a central spacer of small cross sectional area between said overhanging portion of the bail means and the upper end of said portion of the assembly.

21. A combination as set forth in claim 20 in which said spacer is a metal ball welded to one of said overhanging portion of the bail means and said upper end of said portion of the assembly. 

1. In the combination of a ladle having a bottom port to pour molten metal, a stopper rod in the ladle to open and close the bottom port and support structure carried by the ladle to support and control the stopper rod, the improvement comprising: the stopper rod being equipped for cooperation with a crane to lift the stopper rod out of the ladle; said support structure being equipped with attachment means to releasably connect the stopper rod to the support structure; said attachment means being variable between a first state to connect the stopper rod to the support structure and a second state to release the stopper rod from the support structure; and a latch to releasably retain said attachment means in its first state, said latch being responsive to lifting force on the stopper rod by a crane to release the attachment means for shift from its first state to its second state to release the stopper rod from the support structure.
 2. In a combination of a ladle having a bottom port to pour molten metal, a stopper rod to close and open the bottom port and support structure mounted on the ladle to control the stopper rod, the improvement comprising: attachment means having a first state to connect the stopper rod to said support structure and a second state to release the stopper rod from the support structure; bail means on the stopper rod engageable by a crane to lift the stopper rod out of the ladle; and means to shift the attachment means from its first state to its second state in response to lifting force exerted on the bail means, thereby to release the stopper rod from the support structure.
 3. In a ladle having a bottom port to pour molten metal, wherein a stopper rod normally closes the bottom port and the stopper rod is releasably connected at its upper end to support structure on the ladle, the combination of: an engagement member on said support structure movable between a first effective position to engage the stopper rod to connect the stopper rod to the support structure and a second release position to release the stopper rod from the support structure; means to latch the engagement member at its effective position; and bail means on the stopper rod for engagement by a crane to lift the stopper rod out of the ladle for replacement of the stopper rod after a pouring operation, said bail means being movable relative to the stopper rod with lost-motion between a lower relaxed position and an upper load-bearing position to support the stopper rod from the crane, said latch means being operatively connected to the bail means for release in response to upward movement of the bail means to its upper weight-bearing position, whereby engaging the crane with the bail means and lifting the bail means to raise the stopper rod out of the ladle causes the latch means to release the engagement member for release of the stopper rod from the support structure.
 4. A combination as set forth in claim 3 in which said engagement member at its first effective position extends into the path of vertical movement of the stopper rod and at its second release position is retracted for reduced interference with lowering of a replacement rod into the ladle.
 5. A combination as set forth in claim 3 in which said engagement member is rotatable between a lower effective position and an upper release position.
 6. A combination as set forth in claim 5, in which a portion of the engagement member moves in an arc between its two positions; and in which said portion of the engagement member is shaped and dimensioned to shift the stopper rod laterally away from the support structure in the arcuate movement of the engagement member from its effective position to its release position to keep components on thE stopper rod from catching on said support structure in the ladle in the course of the upward movement of the stopper rod.
 7. A combination as set forth in claim 3 in which the stopper rod has a first lateral projection shaped and dimensioned to engage a fixed portion of said support structure from above the fixed portion and the stopper rod has a second lateral projection for engagement with the engagement member from below the engagement member, whereby the first lateral projection may cooperate with the fixed portion of the support structure to resist downward axial movement of the stopper rod relative to the support structure and the second lateral projection may cooperate with the engagement member at its effective position to resist upward axial movement of the stopper rod relative to the support structure.
 8. A combination as set forth in claim 7 in which at least one of said first and second lateral projections is adjustable towards the other to tighten the engagement of the support structure with the stopper rod.
 9. The combination of: a ladle having a bottom port for pouring molten metal; a stopper rod to control the bottom port; support structure for the stopper rod carried by the ladle; attachment means on the support structure; and an assembly on the stopper rod for engagement by the attachment means, said attachment means being variable between an effective state to engage the assembly and a release state to release the assembly for withdrawal from the ladle of the stopper rod with the assembly thereon; said assembly including: means for engagement by said attachment means in its effective state to connect the stopper rod to said support structure; a latch to releasably hold the attachment means in its effective state; bail means for engagement by a crane to lift the stopper rod and the assembly thereon out of the ladle; and means to release the latch in response to the application of lifting force to the bail means to cause the attachment means to release the stopper rod and the assembly thereon for withdrawal from the ladle by the crane.
 10. A combination as set forth in claim 9 in which said attachment means includes both a portion of the support structure and an engagement member rotatably mounted on the support structure; in which said assembly has an upper lateral projection to engage said portion of the support structure from above; and in which the assembly has a lower lateral projection to engage said engagement member from below.
 11. A combination as set forth in claim 10 in which at least one of said two projections is adjustable relative to the other to permit tightening of the engagement of the attachment means with the assembly.
 12. A combination as set forth in claim 10 in which one of said projections is slidable along the stopper rod and is backed by nut means on the stopper rod for adjustment of the one projection relative to the other projection.
 13. A combination as set forth in claim 10 in which said latch is operable to releasably interlock the engagement member with the support structure.
 14. A combination as set forth in claim 9 in which said assembly is releasably mounted on the stopper rod.
 15. A combination as set forth in claim 9 in which said assembly is internally screw threaded for engagement with an external screw thread of the stopper rod to mount the assembly on the stopper rod.
 16. A combination as set forth in claim 9 in which said bail means is connected to the stopper rod with lost motion between the bail means and the stopper rod; and in which said latch is releasable in response to said lost motion.
 17. A combination as set forth in claim 16, in which said assembly has an upwardly extending portion anchored to the stopper rod; in which said bail means is slidably telescoped over said portion to provide said lost motion; in which said portion has an outer downwardly facing shoulder and the surrOunding bail means has an upwardly facing inner shoulder to contact said downwardly facing shoulder at the upper load-bearing position of the bail means; and in which cooperating means on said portion and the bail means respectively cooperate to limit the downward movement of the connector relative to said portion at the lower relaxed position of the bail means.
 18. A combination as set forth in claim 17 in which said cooperating means comprises an upwardly facing outer shoulder on said portion of the assembly and a downwardly facing inner shoulder on the surrounding bail means.
 19. A combination as set forth in claim 17 in which a portion of the bail means overhangs the upper end of said portion of the assembly and rests on said upper end at the lower relaxed position of the bail means.
 20. A combination as set forth in claim 19 which includes a central spacer of small cross sectional area between said overhanging portion of the bail means and the upper end of said portion of the assembly.
 21. A combination as set forth in claim 20 in which said spacer is a metal ball welded to one of said overhanging portion of the bail means and said upper end of said portion of the assembly. 